Vacuum leak check valve



March 16. 1954 J. R. MORIN ET AL VACUUM LEAK CHECK VALVE 2 Sheets-Sheet1 Filed Dec. 19, 1950 INVENTORS JOSEPH R.MORH \I ERIC L. MIDGLEY AKAYMOND P. CROWLEY We. 4% ATTORN -Y March 16, 1954 J. R. MORlN ET AL2,672,266

VACUUM LEAK CHECK VALVE Filed Dec. 19, 1950 2 Sheets-Sheet 2 INVENTORS FQ C L MISGL Q ERAYMO'ND g CROWLEY ATTORN Y Patented Mar. 16, 1954 UNITEDSTATES ATENT OFFICE VACUUM LEAK CHECK VALVE Joseph R. Morin, Ipswich,Eric L. Midgley, Salem,

and Raymond P. Crowley, Danvers, Mass, as-

ors to Sylvania Electric Products Inc.,

2 Claims.

This invention relates to vacuum systems for electric lamps, radiotubes, gaseous discharge devices and the like, and more particularly toa leak check valve therefor.

In the manufacture of electric lamps, radio tubes, gaseous dischargedevices and the like, these articles are usually evacuated on high speedmachinery where several of them are connected through a manifold to acommon vacuum pump. Usually two or morevacuum pumps are employed, onebeing termed a rough vacuum and the other a fine vacuum. The former isemployed. at the start of the evacuation process and then the latter isused. In some cases depending on the nature of the article and thedegree of evacuation desired, more than one rough vacuum pump and/ormorethan' one fine vacuum pump are employed.

One of the problems involved in the simultancous evacuation of severalarticles by one pump is that of isolating a leaky article from theothers to prevent their contamination. One of the mechanisms commonlyemployed to effect isolation of a leaky article hasbeen a mechanicalpinching device disposed in the resilient vacuum line near the exhausthead to which each article is connected. This mechanical pinching deviceis usually actuated electrically by a relay which is, in turn, energizedby a leaky article. Since it is not practical to have a completepinching device assembly for each machine head, usually only one isemployed since most leaky articles are discoverable on rough exhaust.Thus the pinching device assembly is usually located at the last roughexhaust station, immediately preceding the fine exhaust, and the leakyarticle is thereby prevented from contaminating the other articles onfine exhaust.

Although most of the leaky articles are discoverable on the roughexhaustin some cases the leak does not develop or is so small that it isnot discoverable until later in theexhaust operation. In order toprotect the system 'fromicontamination in cases of this type, one ormoreupinching devices should be employed in the fine vacuum system aswell as in the rough vacuum system. Even when this is .done'hoWev-er,the time lag hetween the development of "a. leak and isolation-of theleaky article is usually too great to: prevent contamination of thesystem and the other article connected thereto; In some-cases, the

leak is so small that it goes undetected, yet it is large enough tocause' contamination. oi the system.

It is, therefore aniobject-oii this invention-to 2 detect thedevelopment of a leak in an article during the evacuation thereof.

Another object of this invention is to provide a vacuum leak check valvewhich will immediately isolate a leaky article.

A further object of this invention is to provide a vacuum leak checkvalve which is fully automatic in its operation.

A further object is to provide a vacuum leak check valve which resetsautomatically.

The foregoing objects and others are attained, in accordance with theprinciples of our invention, by providing a chamber in the exhaust lineof a vacuum system, the chamber containing a ball which normally restsout of a seat in the exhaust line. When actuated by an excessive inrushof air from an exhaust head, the ball moves oil" of the shelf and dropsinto this seat in the exhaust line and tightly seals off the exhaustline from the exhaust head. Re-setting of the ball in its normalposition on the shelf is effected by a magnet which moves the ballthereto from the ball seat.

A specific embodiment of our invention is described in the followingspecification and illustrated in the accompanying drawings in which:

Figure 1 is a fragmentary plan view of a flucrescent lamp exhaustmachine.

Figure 2 is a fragmentary side elevational view of a fluorescent lampexhaust machine taken along the line 2-2 of Figure 1.

Figure 3 is a plan view of the vacuum leak check valve of our invention.

Figure 4 is a side elevational view of the valve in section taken alongthe line 4-5 of Figure 3.

Figure 5 is a view partly in section of a modified part of theembodiment of the invention.

In Figures 1- and 2, that portion of a fluorescent lamp exhaust machineshown therein comprises a rotatable turret i supported on a verticalcolumn 2. The turret I comprises a hub 3, a plurality of supporting arms4 extendin radially therefrom, and a ring plate 5 mounted on the outerends of the arms 4. A plurality of lamp exhaust heads 6 are mounted onthe top face of the ring plate 5. As may be seen in Figure 2, the ringplate 5 is provided with an aperture '1 therein in register with eachexhaust head 3, through which an exhaust tube 8 of 'a fluorescent lamp 9extends. The lamp 9 is supported in position on the exhaust machine byfingers it. A leak check valve ll is mounted on the top face of the ringplateS adjacent to each exhaust head 6, the valve H and the headt beingconnected toone another by acoupling l2. The leak check valve ii is alsoconnected to a vacuum pump (not shown) through an exhaust line I3 and amanifold I4.

Referring now to Figures 3 and the leak check valve I I comprises a bodymember I5 having a chamber I6 therein. One end of the body member I5 hasan aperture I'I therein, through which the chamber I6 is connected tothe exhaust head 6 through the coupling I2. The body member I5 has ashelf I8 formed therein in the chamber IS on which a metal ball I9 isnormally disposed. The shelf is tilted back slightly so as to tend tohold the ball in position. The base of the body member I5 is providedwith a plug 20, one end of which is provided with a flange 2I on which aring 22 of resilient material, circular in cross-section, is seated. Asleeve 23 encircles the plug 20, one end thereof engaging the ring 22. Asecond ring 24 of resilient material, circular in cross-section,encircles the plug and engages the other end of the sleeve 23. A thimble25 is disposed on the plug 20 beneath ring 24. Ring 22, sleeve 23, ring24 and thimble 25 are retained in position by a knurled nut 26 on thebottom of the plug 20.

The wall of the body member I5 is provided with an aperture 21 in whichan exhaust line coupling 28 is threaded. The top of the plug 29 iscounter-bored to provide a hole 29 therein. Communication between hole29 in plug 29 and the coupling 28 is established by providing the wallof the plug 20 and the wall of the sleeve 23 with a hole or a pluralityof holes in register with one another and in register with the bore ofcoupling 28. The top of plug 20 is dished about the periphery of hole 29and a ring 3'1 of resilient material, circular in cross-section, isdisposed therein, thus providing a seat for the metal ball I9 when theball is located in this portion of chamber I6.

Referring now to Figures 1 and 2, a pair of arms 3I, one of which isshown, are attached to the vertical column 2 above the manifold I4. Aplate 32 is mounted on the outer end of the arms 3I. A pair of arms 33are attached to the plate 32, their outer ends being disposed above thering plate 5 of turret I. Magnets 34 and 49, held in yokes 35, mountedin ball-and-socket joints 36 depend from the outer end of arms 33. Themagnets 34 and 40 are disposed immediately above the leak check valvesII mounted on the ring plate 5 of the turret I. The use ofball-and-socket joints 36 permits considerable adjustment of thedisposition of the magnets 34 and 39.

In Figure 4, the ball I9 is shown as a hollow metal sphere which seatson the ring 37 when actuated by a leaky lamp. In Figure 5 an alternativemodification of the ball is shown. The ball of Figure 5 is a hollowrubber sphere 38 with a filling of metal filings 39. When thismodification is employed, the ring 31 is not necessary, the rubber ball38 seating directly in the dished portion on the top face of the plug29, thereby effecting the desired sealing off of the exhaust head fromthe vacuum line.

The operation of the leak check valve of our invention will now bedescribed. The fluorescent lamp 9 is positioned on the exhaust machineat station A (Fig. 1), with the exhaust tube 8 thereof in communicationwith the exhaust head 6 (Fig. 2). It will be assumed, for the purpose ofdescribing this particular cycle of operation, that, at station A, themetal ball I9 is disposed on shelf I8 as shown in Figure 4. The exhaustmachine turret I is then indexed, causing the lamp 9 to move tostationB. At station B, the leak check valve I I is disposed beneath themagnet 34 which is of sufficient strength to draw the ball (Fig. 4)upwardly and hold it against the top wall of the chamber I6. With theball I9 in this position, an unobstructed path is provided from the boreof exhaust head coupling I2 into chamber I6. At station B, the lamp 9 isconnected, through exhaust head 6, leak check valve II, and exhaust lineI3 to a rough vacuum pump. As the lamp 9 moves from station B to stationC, the adjacent legs of the two magnets 34 and 40 retain the ball I9against the top wall of the chamber I6, and keep it there while the lampis subjected to a further rough exhaust at station C. At station D,where further rough exhaust is effected, the ball I9 is under theinfluence of the magnet 40 and is therefore still retained in theelevated position just described.

As the lamp 9 moves from station D to station E, the ball I9 movesoutside the magnetic field and therefore drops down to the positionshown in Figure 4, on the shelf I9. At station E and at severalsucceeding stations, the lamp 9 is subjected to a fine exhaust. Sincemost of the air was pumped out of the lamp at stations B, C, and D,normally the force exerted by the gases being drawn off at station E andsubsequent stations is not great enough to blow the ball I9 off of itsshelf I9. However, as soon as a leak develops, an abnormally high flowof gas from the exhaust head 9 will occur and blow the ball I9 off ofthe shelf I9 and cause it to seat on the ring 37. The pressure appliedby this abnormal flow of gas into the chamber I6 against the ball I9(shown in phantom, Fig. 4) will cause the ball i9, in cooperation withthe ring 31, to seal off the chamber I6 from the exhaust line I3. Inthis way, the leaky lamp is automatically and instantaneously isolatedfrom the exhaust line I3 and hence from the rest of the evacuatingsystem. Thus the rest of the system is protected.

from contamination by the leaky lamp.

The ball I9 remains in the position shown in; phantom in Figure 4throughout the remainder of the rotational cycle of the turret I. Theleaky lamp is finally removed by an operator at a station immediatelypreceding station A. At station A a new lamp is inserted. When this newlamp is moved to station B, the ball I9, under the influence of themagnet 34, will be unseated and drawn upwardly thereby, thus providingan unobstructed path from the chamber I6, through the hole 29 in plug 20to the bore of the vacuum line coupling 29. Thus the rough pumping atstation B is unimpeded. As the lamp moves from station B to station C,the ball I9 is drawn by the magnet 34 across the top wall of chamber I6until it reaches a position immediately above the opening I! in the wallof the body member I5. The magnet 34 is angularly disposed as shown inFigure 1 in order to make possible this movement of ball I 9 across thetop wall of chamber IS. The magnets retain the ball I9 in this positionuntil the lamp moves from station D to station E. At this point, theball I9 drops down to the position shown in Figure 4, as describedabove. The ball I9 remains on the shelf I8 for the remainder of theexhaust cycle provided the lamp is not a leaker. If the lamp is leaky,the ball I9 will be dislodged as described above.

The metal of which the several parts of the valve II is made is anon-magnetic material, except that the ball I9 is, of course, made of amagnetic material so that its position may be controlled by the magnets34 and 40.. Similarly,

5 in the modification shown in Figure 5, the metal filings 39 are madeof a magnetic material.

What we claim is:

1. The combination, with a rotatable turret having a pulurality ofexhaust heads mounted about the periphery thereof and a plurality ofvacuum lines extending radially from the center of the turret to theexhaust heads, of a vacuum leak check valve disposed in each of thevacuum lines between the exhaust heads and the center of the turret, thebody of said valve being of non-magnetic material and having a chambertherein normally in communication with the exhaust head and the vacuumline; a ball of magnetic material disposed in said chamber andactuatable by an abnormal flow of gas from an exhaust head to seal offsaid chamber from the vacuum line; and a magnet disposed above and inregister with at least one of said vacuum leak check valves forautomatically breaking said seal.

2. The combination, with a rotatable turret having a plurality ofexhaust heads mounted about the periphery thereof and a plurality ofvacuum lines extending radially from the center of the turret to theexhaust heads, of a vacuum leak check valve disposed in each of thevacuum lines between the exhaust heads and the center of the turret, thebody of said valve being of non-magnetic material and having a chambertherein normally in communication with the exhaust head and the vacuumline; a shelf in said chamber, said shelf being inclined upwardly fromthe horizontal; a ball of magnetic material normally disposed on saidshelf and actuatable by an abnormal flow of gas from an exhaust head toseal ofi said chamber from the vacuum line; and a magnet disposed aboveand in register with at least one of said vacuum leak check valves forautomatically breaking said seal and returning said ball to said shelf.

JOSEPH. R. MORIN.

ERIC L. MIDGLEY. RAYMOND P. CROWLEY.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,518,461 Smith Dec. 9, 1924 1,933,322 Fagan Oct. 31, 19332,254,905 Mullan Sept. 2, 1941 2,565,298 Groat Aug. 21, 1951

